In a brake control device of a rail car, from a fail-safe point of view, commands of a plurality of systems are input to the brake control device. Based on any one of the commands, a relay valve adjusts, for example, air pressure from an air source and output the pressure-adjusted air to a brake cylinder, whereby a brake of a rail car can be controlled based on the commands of a plurality of systems.
In an air brake device of an electric rolling stock disclosed in Unexamined Japanese Patent Application Kokai Publication No. 2001-18784 and a brake control device used for a rail car disclosed in Unexamined Japanese Patent Application Kokai Publication No. H8-290765, when a skid of a car is detected, skid control is performed to control a pressure of air output by a relay valve using a solenoid valve.
A solenoid valve controlling an output of a relay valve is larger than a solenoid valve controlling a command pressure input to the relay valve. In the air brake device of an electric rolling stock disclosed in Unexamined Japanese Patent Application Kokai Publication No. 2001-18784 and the brake control device used for a rail car disclosed in Unexamined Japanese Patent Application Kokai Publication No. H8-290765, since a solenoid valve provided for skid control by an output of the relay valve is large, an enlarged device size has been a problem. Further, there is a brake control device performing control in such a manner that command pressures of two systems are provided for a relay valve, and air on a higher-level priority basis, in other words, air based on a higher command pressure in the relay valve is output to a brake cylinder. In the relay valve of this brake control device, regardless of a magnitude relationship between the command pressures of two systems, when brake control and skid control are performed, it is necessary to provide a solenoid valve for skid control for each of the plurality of command pressures. Accordingly, the device size is enlarged.